Improved steam-engine



UNITED STATES PATENT OEEICE.

JOHN B. ROOT, OF NEW YORK, lN. Y.

IMPROVED STEAM-ENGINE.

Specification forming part of Letters Patent No. 39.957, dated September 15, 1863.

To all whom, it may concern:

Beit known that 1. JOHN B. ROOT, ot' the city, county, and State ot' New York, have invented certain new and useful improvements in engines for obtaining motive power from steam or other fluid, also partly applicable to pumps; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification.

' The principal feature of this invention consists in the combination ot' two pistonsone otA which is hollow and fitted within a parallel-sided box, which may be, termed the cylinder ot' the engine, in such manner as to be capable ot' areciprocating rectilinear motion therein, and the other is fitted tothe interior ofthe first one in such manner as to be capable otl a reciprocatingr rectilinear motion therein in a direction at right angles to the first-mentioned reciprocating rectilinear inotion, and the inner one is connected directly with a crank.

In an engineto be used as amotor, the steam or other iiuid from which thepower is obtained is admitted by a suitable valve or valves t0 the Outer box or cylinder, and to the iutcrior ot' the outer piston in such manner as to act irst on one and afterward on the opposite side ot' each piston and to commence operating on either side ot' one piston when the other pistou is at haltstroke, so that it acts upon both pistons at once t-o produce a rotary motion ot the crank, which' is thereby made to transmit the power without ever be ing at a dead-point.

In a pump the motion ofthe crank produced by al suitable application of power to its shaft sets the two pistons in motion at right angles to each other, and the water or other iiuid is thereby drawn into and expelled from the cylinder and outer piston through a suitable valve or series ot valves.

The invention also consists in a mode of l preventing; the leakage of steam between the surfaces of the sides of the piston and the cylinder-heads of the engine, Yand for compensating for the wear ot' those parts ot' the engine.

It also consists in the employment, for the induction and eduction of stea-m or other fluid to and from an engine or pump having such a well lubricated.

system of pistons as above mentioned, of a valve composed ot' a tlat disk or ring with an annular cavity in its face, and fitted directly to an eccentric, which is provided upon the crankshaft, and is arranged within the steamchest or induction-chamber. Theseat against which this valve works contains tour ports, two of which communicate with' opposite ends of the cylinder, and two with the interior of the larger or outer piston on opposite sides ot' the smaller or inner one, and the valve, deriving from thc eccentric an eccentric circular motion, is made to uncover each port in turn for induction and bring each in turn into coinmunication with the annular cavity in its t'ace, which is always in communication with an annular eduction-channel formed in the seat.

It further consists in a mode of providing for the shifting of' the aforesaid eccentric on the crank-shaft tor the purpose ot' changing the relation of the valve to the pistons in suoli manner as to produce the revolution of the engine in one direction or the other, or et't'ect its reversal.

The invention relates, i ally, to a mode of lubricating the crank-wrist and its bearing. These being within the inner piston cannot be reached by any ordinary means ot' lubrication, and, owing to their being always highly heated by the steam when the engineis in operation, it is especially desirable that they should be Figure l in the accompanying drawings is an elevation taken perpendicular to the main shaft of a steanrengine, illustrating the several features of the invention, representing the valve-chest cover removed to expose the valve to View. Fig. 2 is a vertical section right through the cylinder and pistons ot' the engine in a plane parallel with Fig. l. Fig. 3 is a vertical section directly throughand parallel with the axis of the shaft of the engine. Fig. 4 is an inside face view ot' one of the cylinder-heads. Fig. 5 is ah'orizontal section of the cylinder-head and packing-plate in the plane indicated by the line xx in Fig. 4. Fig. 6 is a diagram illustrative of the construction and arrangement of the valve-ports. Fig. 7 is a A of its form, but because it corresponds in its functions with the cylinders of other engines. The form of the interior of this cylinder is parallelopipedal. lts body is made double, to form a jacket, a, and one or both of its heads, B and C, are movable. Both are represented movable in Fig. 3.

D and E, Figs. 2 and 3, are the pistons, both fitted to work steam-tight between the cylinder-heads. These pistons may be packed to one ofthe said heads with springing or adjustable packing of any suitable kind to compensate t'or wear ofthe surfaces ot' the pistons Vand cylinder-heads; but I prefer to employ an adjustable plate, which will be hereinafter more fully described, instead ot' any other packing. The outer piston, D, consists sim ply of an open frame, the length of which is exceeded by the length of the cylinder by at least twice the length of the crank ofthe engine, and the said piston is iitted steam-tight between the upper and lower sides of the cylinder and packed thereto by spring-packing b b, as shown in Fig. 2. The inner piston, E, is made of a depth from top to bottom which is as much less than the vertical depth of the interior ofthe outer piston, D, as the length ofthe exterior ot' the latter is less than the length of the cylinder, and the said piston E is fitted to work steam-tight between the iiat upright sides ot' the piston D and packed Athereto with elastic or other packing c c d d.

'lhe steam-chest F is formed within or secured to the cylinder-head B, and of its four ports, c c f j", two, e e', communicate with opposite ends of the cylinder outside ot' the pision D, and two with the interior ot' the piston D, one above and the other below the piston E. The main shaft or crank-shaft G of the engine worksin bearings in the centers of the two cylinder-heads, and another bearing is provided for it in a standard, H, outside ot' the cylinder. The wrist plates or arms G G2 of the crank are received in cavities formed in the piston E, and the wrist g is received in a bearing provided forits reception in the center of the said piston. Steam admitted to and exhausted from the cylinder A by the ports e and e alternately produces a reciprocating movement of the piston D within the cylinder, and steam admitted to and exhausted from the interior of the piston D by the ports f and j" a1- ternately produces a reciprocating motion of the piston E within the piston D at right angles to the movement of the latter within the cylinder, while the piston D is at the saine time moving with E, and the force ofthe steam acting' on both pistons is made instrumental in producing a rotary movement of the crank and its shaft. The admission or induction of steam to the ports e e should commence when the piston E is at half-stroke, and the induction tofj commence when the piston D is at half-stroke.

The order in which the induction to the four ports should commence wlll vary according to the direction in which the shaft is intended to rotate. For the direction indicated by the arrows 10 in Figs. 1 and 2 the order will be e fej", and for the opposite direction it will be ef e'f.

In order to reduce as much as possible the friction between the piston D and the cylinder, recesses 17 17 are formed all across the upper and lower faces of the said piston for the greater portion of their length, as shown in Fig. 2, for the admission ot steam between them and the upper or lower side of the cylinder, and corresponding recesses 1S 18 are formed in the sides of the said piston, as shown in Fig. 3, and by dotted lines in Fig. 2, to allow steam to pass from the interior ot' the said piston to the recesses 17 17. This leaves only a sufiicient portion of the ends of the piston to insure tight working', lifting between the heads of the cylinder, and the steam in the recesses 17 17 counteracts the upward and downward pressure of the steam against the upper and lower sides ot' the said piston, and soprevents the excessive friction which would otherwise be produced between the said piston and the cylinder. To reduce in like inanner the friction between the sides ot the piston E and the interior ofthe piston D, recesses 19 19 are made in the outer side faces of E, and small holes 20 2() providedin the upright ends of D, as shown in Fig. 2, to admit steam from the cylinder A into the said recesses. rlhe adjustable side plate, which is employed for keeping the pistons steam tight within the cylinder, is shown at the right side ot Fig. 3, fitted to the cylinder-head C, and as also shown in Fig. 5. (indicated by the letter Q.) This is simply a rigid flat plate, ofeast-iron or other metal, of a form corresponding with the longitudinal vertical section of the cylinder, which is shown in Fig. 2, and having a central opening for the crankshaft bearing, and it is fitted into a recess, 2, of corresponding t'orm, in the interior of the head C. No packing is employed in the opposite head, which is simply faced flati'orthe pistons to work in contact with. In Fig. 3 the plate Q is represented as adjusted to the sides of the pistons by means of set-screws n a, screwing through the head O from the eX- terior thereof', and is thereby not only held against the contiguous sides of the pistons in such manner as to form a steam-tight working joint, but made to hold the opposite sides ot` the pistons against the head B in such manner as to keep them steam-tight, and the wear of the pistons on both sides ofthe engine is compensated for by screwing up the screws e c. ln Fig. 5 the said plate Q is represented as adjusted to the pistons by means of wedges y y, formed upon the outer face of a frame, lt, which is arranged between the said plate and the cylinder-head C in the inner part of the recess 21. This frame R is also shown in Fig. 4. The wedges y y are arranged in two seriesone series on the upper and the other one on the lower side of the said frame-and work in contact with corresponding inclined surfaces z z, provided in the recess 21, as shown in Fig. 5. The adjustment of the frame R is effected and secured bymeans of a set-serer at each end of the cylinder, screwingthrough tappeti holes in the said cylinder-head and bearing against the ends of the said frame, and by this adjustment all the Wedges are brought simultaneously into opera-tion to press the plate Q against the pistons, and as they are all of similar inclination all act equally upon the plate, and so press all parts equally against the pistons.

The advantage of the employment ofthe Wedges attached to a frame. R, over the use of the setsciews a a is that their uniform action on all parts of the plate is obtained by a single screw at each end ofthe plate, while the screws c e require to be adjusted separately, and it is ditlicult, if not impossible, to make all press exactly-alike against the plate Q.

I, Figs. 1, 3, and 7, is the valve for the induction and eduction of steam, consisting` of a circular disk or ring, having an annular cavity, i, in its face, which is otherwise flat and tted to the flat seat j, provided in the steamchest, the said seat being perpendicular to the axis of the main shaft G, and parallel with the plane of motion of the piston E. The hack of this valve is fitted to Work against the flat inner surface of the steam-chest cover F', and provided with suitable packing, j, so that the steam only occupies the portion of the chest around the peripheryT of the said valve. The central opening, k, of the valve is titted loosely to the eccentric J, which is carried by the main shaft, and the valve is thereby caused to have an eccentric circular motion, by which itis caused to open the several ports successively to the steam-chest and to bring them successively into communication with the annular exhaust-channel I, which is provided in the valve-seat and arranged concentric with the shaft G, the latter communication being made through the annular cavity t' in the valve-seat. The form of the outer orces ofthe ports c c ff is illustrated in Fig. l, and in the diagram, Fig. 6. 'l`he inode of settingvout these orifices is as follows: First, strike around the center of the sea-t coinciding with the axis ofthe main shaft a concentric circle, 12, and draw through the center of the said circle a horizontal right line, 15 15, and a vertical right line, 16 16; then with a radius equal to half the diameter of the outer circle of the valve, from points to be presently mentioned in the aforesaid circle, strike the lines of the outer edges of the ports, and from the same points, with a radius equal to halt' the diameter ofthe outer circle of the central cavity, strike the lines of the inner edges of the ports. If the valve is allowed to have no lead, the lines are to be struck from the points of intersection of the lines 15 and 16 and the circle 12, but it' alead is required they are struck from points more or less dist-ant fromiopposite sides of the aforesaid points of intersection. In the example represented the valve has a lead and the ports are struck from the points e* eif* fft, as may be found by applying the Compasses to those points. The eccentric is set in advance of the crank G in the direction of their revolution to the extent of ninety degrees of a circle, butto these ninety degrees must be added the required number of degrees oflead, When lead is to be given to the valve. The valve thus constructed and operated will commence opening one of the four ports to the steam in the steam-chest at every quarter-re volution, at the same time opening the opposite port to the exhaust-channel l, the order of their opening being, as before described, according to the direction of the revolution, and the ports each remaining open during halt a revolution of the crank-shaft. As each port is Wide open, and its respective piston at halfstroke, and the crank at or nearly at a right angle With the direction of the reciprocating movement of that piston at thc time when the next port is commencing to open and the other piston is atl the change of its stroke, and the crank in line or parallel with the direction ot its movement, when one piston is exerting the least eifect on the crank, the other is exerting the greatest, and hence there are no dead-points in the operation of the engine. The exhaust-'steam passes from the annular exhaustchaunel l through' any suitable number ot' passages m m, dotted in Figs. 1 and 3,

into the jacket a, and thence by an opening, n, into the hollow bed-plate P, which may also serve as a heater for heating the feed-Water on its way to the boiler. The steam-pipe from the boiler connects with the cylinder at u, and communicates with the chest F by means of a passage, a.

p is the toothed are, q the spurvgear, and` 1' the pinion by which the shifting of the eccentric to set it for producing the rotation of the crank-shaft in one direction or the other is produced. The toothed arc p is arranged andV firmly secured within a cavity, s s', provided in theeceentric. lts teeth are on the inner curve and their pitch-line concentric with the shaft G. lhe spur-gear q, gearing with the said are, is arranged to turn freely upon the pin q', which is carried by a short arm, L, which is secured on the shaft G in such manner as to rotate. with it, the axis of the said pin being parallel with the axis of the shaft. The portion of the shaft which enters and protrudes through the exterior ofthe eccentric J is bored lout centrally for the reception ot' the pinion i", which gears with the gear q, and ofthe spindle r', to `which it is secured, and an opening is cut in one side of the said por-` tion ofthe shaft, to meet the said central bore and admit the teeth ofthe gear q to gear with the pinion r. The spindle 1^ is furnished.l with a fast collar, r2, which covers the end ot the shaft G, and a cap, F2, screwed or otherwise secured to the exterior of the steam-chest cover F', tits against the said collar r2, and secures the spindle i" and pinion r in place,

the said cap having a central opening through which a portion ot' thc spindle protrudes for the reception of the wheel M, to enable the pinion and spindle to be turned by hand or other means, for the purpose of turning the eccentric on the shaft. To prevent any leakage ot' steam around the spindle r the wheel M is arranged against the cap F, and fitted with a packing-ring, t, which is pressed against the said cap by springs. The arm L is so arranged that a portion of it is received within the cavity s s', and it drives the eccentric by coming into contact with one side or other of the said cavity, according to the direction in which the engine is running, and no movement ofthe arc p, gear q, and pinion r, relatively to each other, takes place while the engine continues running in one direction. The said arm L is made ot' such width, and the cavity s s/ of such width or diameter, that the eccentric will be permitted by the said arm to turnl upon and independently ofthe shaft to the extent ot' half a revolution when no lead is given to the eccentric, or to the extent-of halt' a revolution minus double the amount of the lead of the eccentric when lead is given. The eccentric is turned on the shaft to set it, when the engine is at rest, by turning the wheel M, which, by turning the pinion 1', causes the latter to turn the gear q, and this gear operates on the toothed arc p to turn the eccentric. When the engine is in operation, the spindle r rotates with the main shaft G, and whenever it is desired to reverse the motion, all that requires to be done is to stop the wheel M, either by taking hold of it by hand or by applying a friction-brake, or by other means, and thereby stop the revolution of the pinion r until the reversal is effected. The stoppage of the pinion t" while the gear q is carried around it by the continued revolution of the arm L, causes the said gear to turn on the pin q in such a direction that it will, by its action upon the arc p, cause the eccentric to rotate faster than the shaft in the same direction, until the opposite side of the cavity s s to that which has previously been in contact with the arm L comes in contact with thc said arm, and the eccentric and valve are thereby brought to proper position relatively to the crank-wrist g, for effecting the induction and eduction to and from the several ports, in the proper order of succession to change the direction of the revolution ofthe crank-wrist. This action of the pinion may be perhaps rendered more intelligible by describing it with reference to Fig. 1, where the shaft and valve are rotating in the direction ofthe arrows l0, the arm L driving the eccentric by pressing against the side s of the cavity s s', but by.

stopping the pinion r the gear q is caused to rotate upon the pin q in adireetion to turn the eccentric forward upon the shaft in the same direction as the shaft is rotating, and bring thc side s" into contact with the arm L. Vhen the reversal of the action of the pistons upon the crank-wristhas taken place, the

arm L drives the eccentric in the same direction as the crankshaft-that is to say, in the opposite direction to that indicated by the arrows l() lO-by pressing against the side s of the cavity s.

T is an air-tight oil-chamber, formed in the upper part of the cylinder-head C, with a passage, 23, from the bottom leading directly to the crankshaft bearing 22-that is, contained within the said head-and with an openingin the top for supplying it with oil. The upper opening is fitted with a screw-stopper, 30, to make it steam-tight, and the passage 23 is fitted with a cock, 24, to enable it to be closed during the time that the chamber T is being` filled. There is also a passage, 25, leading from the steam-passage u into the upper part of the said chamber, and the said passage is fitted with a valve, 26, which can be opened and closed by a screw or other device operated by a handle, 27, outside of the cylinderhead. The passage 25 communicates with agroove or channel in the interior ot" the bearing 22, and this channel communicates with a passage, 28, which is drilled in the center of the crank-wrist g and through the wrist-plate or arm G', and from which there branch off the radial passages 29 29, drilled from the periphery of the wrist, to communicate with the bearing 3l. To fill the chamber T with oil, the cock 24c is closed to prevent the steam from flowing through the passage 23 from the interior of the cylinder A, and the valve v26 is closed to prevent the steam in the passage u from blowing through the passage25, and the stopper 30 is then removed and the oil poured into the chamber. NVhen the chamber has been charged with oil,the stopper is replaced, and when it is desired to oil the crank-wrist bearing the cock 24 and the valve 26 are opened, and steam, entering the upper part of the chamber and pressing upon the upper surface of the oil, forces a portion of it through the passage 23, the channelin the bearing 22, the passage 23 in the wrist-plate or arm and wrist, and the passages 29 in the wrist. This oiling operation may be performed periodically, or may be made continuous by leaving the valve 26 and cock 24C a little way open to allow the oil to tlow to the bearing 3l.

To prevent the cutting of the crank-wrist and its bearing, I propose to iit the wrist tightly witha sleeve, 32, ot hardened steel, and to make the lining of the bearing of an alloy composed ot' copper, with very small proportion of tin.

The leakage of steam through the crankshaft bearing 22 is prevented by a collar, U, which is fitted tightly to and secured upon the shaft close to the cylinder-head C, and fitted with a packing-ring 33, which is held up to the cylider-head by springs.

A pump may be constructed in precisely the same manner as the steam-engine, and operated by power applied directly to the shaft outside of the cylinder to produce its rotary motion, the suction-pipe being connected at a and the discharge-pipe with the jacket a, or directly with the channel lin the valve-seat, the jacket being unnecessary. The rotary motion of the shaft produces the same reciprocating movements of the two pistons and the eccentric circular motion of the Valve as is produced by the action of the steam upon the pistons, and by these movements of the pistons the water is drawn into the cylinder A, through the ports e and e', and into the piston D through the ports j' and j", and forced out through the same ports into the channel l; but it is obvious that in a pump, as in an engine, and more especially in a pump, the same system of pistons may be made to work in the same way with a dii'erent valve or system of valves.

What I claim as my invention, and desire to secure by Letters Patent, is

1. The two pistons D and E, combined with each other and the cylinder A, and crank-shaft G, to operate substantially as herein specied.

2. The packing-plate Qt, applied in combination with the cylinder-head O, and the two pistons D E, substantially as andfor the purpose herein set forth.

3. The wedge-frame R and its double series of Wedges Q/ y, applied in combination with the cylinder-head C and packing-plate Q, to operate substantially as and for the purpose herein described.

4. The 'eccentrically-moving disk or ring valve I, constructed with an annular cavity t', and operating substantially as herein described.

5. Gombinin g the valve-operating eccentric J with the crank shaft G, by means ofthe arm L and the toothed gearing p, q, 1", or its equivalent, substantially as and for the purpose herein set forth.

6. Providingfor the lubrication ofthe crankwrist bearing by means of channels or passages made in the wrist and wrist plate or arm ot' the crank, and communicating with the journal box or bearing provided for the shaft in one of the cylinder-heads, substantially as herein described.

7. An engine composed of a cylinder, A, two pistons, D E, workin g one within and at right angles to the other in the said cylinder, a shaft, G, furnished with a crank connecting directly with the inner piston, E, and a valve, I, and system of ports e e j' f', for eifecting the induction and eduction of the steam or other liquid to and from the cylinder and the interior of the outer piston, the whole operating substantially as herein described.

JOHN B. ROOT.

Witnesses:

M. M. LIVINGSTON, DANIEL ROBERTSON. 

